Multi-objective, risk-based approach for safe and sustainable vehicle routing

Vehicle routing is a daily activity to move people and goods from one point to another. Routing is subject to constraints, such as time, distance, and out-of-pocket cost. Traditionally, routing decisions were based mainly on efficiency considerations (i.e., finding shortest path in terms of distance or travel time). With rising global interest in traffic safety and green transportation, there is a need to consider other factors such as risk to humans and environment. In this study, a methodology was developed to provide a comprehensive, risk-based vehicle routing approach to account for various objectives (or risks), including: travel time, travel distance, travel cost, accident risk, air emissions risk, and noise risk. The methodology involves three major steps: first, estimation of the various risks for individual road links; second, integration of the individual risks into a single comprehensive risk measure using the Analytical Hierarchy Process (AHP); and finally, finding the preferred (i.e., least risky) route based on risk. The framework is implemented inside a Geographic Information System (GIS) environment. The proposed methodology was applied to a real-world setting: Sharjah City, United Arab Emirates. Outcomes are charted in the form of least-risky routes for a selected origin-destination pair taking into consideration each objective individually or in combinations, in addition to comprehensive risk. The proposed methodology provides a way to integrate environmental and safety related measures into vehicle routing, which is a step towards making the transportation system safer and greener.